Most golf balls currently in use have one of three types of cores: solid, wound, or liquid. The different types of cores result in golf balls having different characteristics, especially in the feel of the ball when struck. Generally, a soft feel is desirable to a skilled golfer, and this can be achieved using a softer core material.
Solid cores are formed of various materials including polybutadiene, natural rubber, metallocene catalyzed polyolefin, polyurethane, other thermoplastic or thermoset elastomers, and mixtures of one or more of these materials. The core material is generally in the form of a slug which is compression molded to form a spherical core. The cores may be formed from a uniform composition or may have two or more layers. Though the cores produced from these materials are solid, the materials provide a soft feel to the ball.
Typically, core material is heated and extruded to form an elongated slug which is cut into pieces to form the individual core slugs. The heated slugs are stored in bulk for eventual delivery to a molding cell. At the cell, a plurality of slugs are manually arranged in the proper orientation in a mold press to simultaneously form a plurality of cores.
One major drawback of the conventional golf ball core forming techniques is that the heated slugs from the extruder cool during storage. Another drawback is that extruded slugs must be powdered to prevent them from sticking to one another during bulk storage. Some materials used in the powdering process cause early failure of mold coatings and reduce the durability of some cores. A further drawback is that human errors result in misaligned slugs which in turn results in defective cores. In addition, the proximity of human operators to the mold press for slug loading and core unloading limits the temperature of the molds for operator safety.
The present invention was developed to eliminate the need for bulk storage of the slugs, thus conserving internal heat from extrusion, eliminating the need for powdering, and reducing mold cycle time. Moreover, the invention was developed to eliminate misalignment of the slugs by providing a device for transferring a plurality of slugs from the extruder directly to a core molding press, thereby reducing rejects and improving overall quality of the cores. Operator injury is avoided and the absence of human intervention allows the molds to be heated quicker and cooled less to further reduce cycle time and increase output.
Accordingly, it is a primary object of the invention to provide a slug feeder device including a rotary transfer mechanism including grippers for receiving slugs from a slug extruder and cutter, a conveyor for linearly conveying individual slugs from the transfer mechanism and a gripping mechanism for simultaneously removing a plurality of slugs from the conveyor and depositing them in an array of cavities in a molding tray. The operation of the transfer and gripping mechanisms as well as the conveyor are all controlled for synchronous movement to maximize the efficiency of the feeding operation.
According to a further object of the invention, the grippers on the rotary transfer mechanism are able to detect whether the slugs from the extruder are properly oriented and configured. Those slugs which are defective are released from the grippers of the rotary transfer mechanism prior to the conveyor for recycling. In addition, the absence of a slug from a gripper of the rotary transfer mechanism is detected. The conveyor includes a plurality of receptacles, each of which is adapted to receive a slug from the rotary transfer device. If a slug is not presented to the conveyor by a gripper of the rotary transfer device, movement of the conveyor is delayed until a slug is presented. In this manner, no empty receptacles are conveyed to the gripping mechanism.
According to another object of the invention, the gripping mechanism includes a plurality of grippers which are linearly arranged and spaced above the receptacles of the conveyor for simultaneously removing a selected number of adjacent slugs from the conveyor. The gripping mechanism is movable about six axes to orient the slugs relative to the cavities in the molding tray for simultaneously depositing the slugs in a row of cavities in the tray.